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[CPUFREQ] p4-clockmod: Workaround for CPU's with N60 errata 

Ignore clock frequencies below 2Ghz for CPU's detected with N60 errata bug.

Signed-off-by: Ben Collins <bcollins@ubuntu.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Dave Jones <davej@redhat.com>
This commit is contained in:
Ben Collins 2006-01-18 23:45:39 -08:00 committed by Dave Jones
parent cdc9cc1d74
commit c70ca00f77
1 changed files with 9 additions and 0 deletions
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9
arch/i386/kernel/cpu/cpufreq/p4-clockmod.c
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@ -52,6 +52,7 @@ enum {
static int has_N44_O17_errata[NR_CPUS];
static int has_N60_errata[NR_CPUS];
static unsigned int stock_freq;
static struct cpufreq_driver p4clockmod_driver;
static unsigned int cpufreq_p4_get(unsigned int cpu);
@ -226,6 +227,12 @@ static int cpufreq_p4_cpu_init(struct cpufreq_policy *policy)
case 0x0f12:
has_N44_O17_errata[policy->cpu] = 1;
dprintk("has errata -- disabling low frequencies\n");
break;
case 0x0f29:
has_N60_errata[policy->cpu] = 1;
dprintk("has errata -- disabling frequencies lower than 2ghz\n");
break;
}
/* get max frequency */
@ -237,6 +244,8 @@ static int cpufreq_p4_cpu_init(struct cpufreq_policy *policy)
for (i=1; (p4clockmod_table[i].frequency != CPUFREQ_TABLE_END); i++) {
if ((i<2) && (has_N44_O17_errata[policy->cpu]))
p4clockmod_table[i].frequency = CPUFREQ_ENTRY_INVALID;
else if (has_N60_errata[policy->cpu] && p4clockmod_table[i].frequency < 2000000)
p4clockmod_table[i].frequency = CPUFREQ_ENTRY_INVALID;
else
p4clockmod_table[i].frequency = (stock_freq * i)/8;
}